1. Field of the Invention
This invention relates to photographic apparatus and, more particularly, it concerns an illumination arrangement for use in compact identification card camera systems and by which film is uniformly exposed to a data card image.
2. Description of the Prior Art
Identification card camera systems which produce a composite card having a subject portrait image and a data image are known in the photographic arts. The subject portrait image is produced by a conventional objective lens, shutter, and flash unit arrangement. The camera system includes either a filter or mask to confine the subject portrait image to a particular portion of the film within the camera system. The data image may include identification information such as name, ID number and signature contained in a data frame of a data card. The data image is produced by photographically reproducing at least the data frame portion of a data card housed in an illumination compartment having an internal source of illumination and a lens system separate from the above-mentioned objective lens. The camera system includes reflective elements and filters or masks to direct the data card image to the film and confine the data card image to a portion of the film not subject to the portrait image.
Typically, the data card illumination compartment does not include a shutter and relies on an internal flash illumination source to expose the film. The quality of the data card image on the film depends, therefore, on the quality of flash exposure provided by the internal illumination source. For example, in order to provide for a uniform exposure of the film to a light image of the data card, the illumination source must provide uniform illumination of the data card. In a conventional relatively large sized camera system, uniformity in the illumination of the data card is achieved by use of a large size data card compartment which allows the source to be spaced adequately from the card for dispersion of the illumination prior to reaching the data card.
However, when it is necessary to provide flash illumination of a data card within the confines of a very compact, portable identification card camera system, for example, it is not possible to locate the illumination source an adequate distance away from the data card to allow for dispersion of the illumination. Further, conventional flash illumination sources, such as electronic flash units or strobe tubes, produce an intense non-uniform illumination along their length. Placement of such a conventional flash unit close to the data card, not only does not allow for dispersion to compensate for the different distances between the flash unit and all the areas of the data card, but also does not accommodate dispersion to compensate for the nonuniform illumination along the length of the flash unit. Hence, use of such flash units as illumination sources in the data card compartment of a very compact camera system produces a flash exposure having undesirable hot spots and areas of poor illumination.
Thus, a need exists for an illumination arrangement providing for adequate and uniform illumination of the entire data frame of a data card to provide a uniform flash exposure of the film and at the same time accommodate the dimensional constraints of a compact identification card camera system.